GravityView A-Z: Modify the collation so that filtering works for Polish L and Ł

modify-gravityview-az_filter-collation.php

<?php

/**
 * Override the default query collation for the letter comparison (Requires GravityView A-Z Filters version 1.3 or newer).
 * @param null|string $collation_override The collation override for the query.
 * @param string $query The MySQL query passed to the database.
 * @return string
 */
add_filter( 'gravityview/az_filter/collation', function ( $collation = null ) {
	return 'utf8mb4_bin';
} );